/*
 * Copyright 2002-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package qunar.tc.bistoury.instrument.client.spring.el;


/**
 * Represents a dot separated sequence of strings that indicate a package qualified type
 * reference.
 *
 * <p>Example: "java.lang.String" as in the expression "new java.lang.String('hello')"
 *
 * @author Andy Clement
 * @since 3.0
 */
class QualifiedIdentifier extends SpelNodeImpl {

    // TODO safe to cache? dont think so
    private TypedValue value;


    public QualifiedIdentifier(int pos, SpelNodeImpl... operands) {
        super(pos, operands);
    }


    @Override
    public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
        // Cache the concatenation of child identifiers
        if (this.value == null) {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < getChildCount(); i++) {
                Object value = this.children[i].getValueInternal(state).getValue();
                if (i > 0 && !value.toString().startsWith("$")) {
                    sb.append(".");
                }
                sb.append(value);
            }
            this.value = new TypedValue(sb.toString());
        }
        return this.value;
    }

    @Override
    public String toStringAST() {
        StringBuilder sb = new StringBuilder();
        if (this.value != null) {
            sb.append(this.value.getValue());
        } else {
            for (int i = 0; i < getChildCount(); i++) {
                if (i > 0) {
                    sb.append(".");
                }
                sb.append(getChild(i).toStringAST());
            }
        }
        return sb.toString();
    }

}
